The long-term goal of this study is to understand the neural processing of gustatory stimuli in the central nervous system. Of particular interest is the processing of appetitive (sweet) and aversive (bitter) stimuli in the medullary nucleus of the solitary tract (NTS). Information from appetitive stimuli is transmitted from the tongue to the NTS via the VIIth cranial nerve, whereas information regarding aversive stimuli is transmitted from the tongue to the NTS via the IXth nerve. Taste responses in the NTS are often the result of converging input from these two nerves. The functional nature of this convergence is not well understood, although some evidence suggests the presence of an inhibitory interaction between the VIIth and IXth nerves. The specific aim of this study is to investigate the role of the IXth nerve in this convergence and its influence on gustatory responses in the NTS. In order to study this, the IXth nerve will be selectively and reversibly anesthetized. Responses to the four basic taste stimuli (NaCl, sucrose, QHCl and HCl) will be recorded from single neurons in the NTS before, after and following recovery from IXth nerve anesthesia.